Aqueous bituminous emulsions



Patented May 22, 194

2,37 6,498 AQUEQUS BI'EDUS EMULSIONS assignor to Del, 2.

No Drawing. Application December 5, 1M1,

Serial No. $1,773

6 Claims. ($71. 252-3115) In my copending application, Serial No.303,818,

filed November 10, 1939, now Patent No. 2,265,181, issued December 9,1941, of which this application is a continuation-in-part, there isdescribed a new resinous material prepared by heating ligneous resinouswood, or a mixture of a ligneous substance and a resin acid material, inthe, presence of water at an elevated temperature and undersuper-atmospheric pressure. This resinone material, herein termed wooddigestion resin, is a hard, dark-colored substance, usually having a.drop melting point above about 100 C. In some instances it may melt attemperatures as high as 250 C. In general, it is substantially insolublein petroleum hydrocarbons, such as gasoline, but is readily soluble inacetone, ethanol, ethyl acetate, methanol, methyl isobutyl ketone, butylacetate, and similar organic solvents. It is only partially soluble inaromatic hydrocarbons such as toluene and xylene. Other properties andcharacteristics of this resin are more fully pointed out hereinafter andin the abovementioned parent application.

The present invention is based on the discovery that a wood digestionresin, such as described in the above application, may be saponifiedwith an aqueous alkali, such as sodium or potassium hydroxide, to-form asoap-like product having excellent emulsifying properties. Because ofits low cost, and the good stability and viscosity characteristics ofthe emulsion prepared therewith, this emulsifying agent is particularlyadapted to use in the manufacture of aqueous bituminous and asphalticemulsions or dispersions of the oil-in-water type, such as those sowidely employed. in the road surfacing art. Accordingly, the inventionconsists in the new saponified wood digestion resin emulsifyingagent'and in improved aqueous bituminous and asphaltic emulsionscomprising the same.

The following examples willillustrate several ways in which theprinciple of the invention has been applied, but are not to beconstruedas limiting the same.

7 EXAMPLE 1 A quantity of wood digestion resin, was prepared byimpregnating -150 parts byweicht ofso spent pine wood chips, 1. e.,chips from which the turpentine and rosin had been extracted, with asolution of parts by weight of E Wood rosin in 400 parts by weight ofacetone. The acetone was then removed by evaporation and the impregnatedchips were covered with 550 parts by weight of water in an autoclave.The autoclave was heated at a temperature of about 260-270 C. foroneihour, during which time a pressure of about 950-1000 pounds persquare inch was developed. The autoclave was then cooled and vented torelieve the pressure, after which the resin product was removed andseparated from the water. After heating to drive ofi gases, moisture andothervolatile products, the wood digestion resin was obtained as a.hard, brittle, dark-colored resinous solid, having the followingcharacteristics:

Softening point -L C.... 177 Acid No fl .40 Saponiflcation No 89 Tolueneinsoluble per cent 48 Unsaponifiable tables do.. 10 Ash do 1.3

Approximately 100 parts by weight of this resin was pulverized finerthan 80 mesh and suspended in 250 parts by weight of a 0.4 per cent byweight aqueous solution of sodium hydroxide. A solution of 6 parts byweight of sodium hydroxide in to parts by weight of water was then addedto the resin suspension, and the mixture was stirred to keep the resinparticles in suspension until the saponification reaction was complete.There was thus obtained an approximately 25 per cent by weight aqueousdispersion of the saponified resin. This dispersion was employed inpreparing an aqueous asphalt emulsion as follows: Approximately 20 partsby weight of the saponified resin dispersion (amounting to about 5 partsby weight on a dry basis) was diluted with 400 parts by weight of watercontaining 1 part by weight of sodium hydroxide. The resulting solutionwas then heated to a temperature of about C., and 600 parts by weight ofmolten Texas asphalt was added gradually with rapid stirring. Themixture was then passed through a colloid mill to obtain completeemulsification. The emulsion so obtained had a 93 N. CaCl: demulsibilityvalue of zero, and a N. CaCla demulsibility value of about 45%. Asimilar asphalt emulsion containing 10 parts by weight of the saponifiedresin dispersion had a N. CaCla demuisibility value of about 30%.

Exams: 2

A sample of wood digestion resin prepared by heating equal parts of Bwood rosin and spent pine wood chips in the presence of water wassaponified in the cold with aqueous sodium hydroxide in a manner similarto that described in Example 1. Approximately 32 parts by weight of thesaponified resin dispersion (about 8 parts by weight on a dry basis) wasthen dissolved in 400 parts by weight of water containing 2 parts byweight of sodium hydroxide, and 600 parts by weight of molten Texasasphalt was added gradually with rapid stirring. After passing themixture through a colloid mill there was obtained a stable asphaltemulsion having N. and 1 6 N. CaCl2 demulsibility values of zero, and afurol viscosity of about 26 seconds at 25 C.

EXAMPLE 3 A number of asphalt emulsions were prepared as described inExample 2 employing varying amounts of the emulsifying agent and freesodium hydroxide. The compositions of these emulsions and theirrespective demultibility and viscosity characteristics are tabulatedbelow:

Table Emulsion No. l 2. 3 4 5 6 Asphalt 600 600 600 600 600 600 Water 1400 400 400 400 400 400 Saponified wood diges tion resin (dry basis) 3 58 10 Sodium hydroxide l 1 l l 2 2 2 $50 N. CaCh demulsibility value..per cent. 55 35 Ni] lio N. CaCh demulsibility value. .per cent. 68 52Tracc Nil Nil Nil Viscosity (iurol at C.), Secs 39 29 27 32 67 61 1Parts by weight.

EXAMPLE 4 Approximately 100 parts by weight of the wood digestion resindescribed in Example 1 was pulverized and stirred into 100 parts of'a 10per cent by weight aqueous solution of potassium hydroxide. Stirring wascontinued for several minutes, after which the mixture was heated toboiling to complete the saponification reaction, The saponified resindispersion so obtained was a. thin dark-colored paste containing about50 per cent by weight of solids. Asphalt emulsions in which thisdispersion wa employed as the emulsifying agent were similar to thosedescribed in Example As hereinbefore mentioned, the wood digestion resinwhich is saponified to form the new emulsifying agent provided by theinvention is prepared according to the process described and claimed inco-pending application, Serial No. 303,818, filed November 10, 1939 nowPatent No. 2,265,181, issued December 9, 1941. Such process consistsessentially in heating a ligneous resinous cellulosic material, such aspine wood containing 15-25 per cent by weight of rosin, at an elevatedtemperature, e. g., between about 240 C. and about 330 C., and undersuper-atmospheric pressure while submerged in water until the fibrousstructure of the material is destroyed and resinification takes place.Alternatively, a non-resinous ligneous material may be mixed orimpregnated with a resin acid substance, e. g., crude rosin, and

subjected to the same treatment. According to a preferred mode ofoperation, dead pine stump wood, or a mixture of crude rosin and spentpine wood chips from which th turpentine and rosin have been extracted,is placed in a stainless steel autoclave and covered with water. Theautoclave is then heated to a temperature of about 240- 330 C.,preferably 250-280 C., for a period of time varying from about twominutes to about six hours, depending upon the particular kind of woodand temperature employed. During the heating, the autogenous pressurewithin the autoclave may vary from 400 to 1900 pounds per square inch.The autoclave is then allowed to cool and is vented to release thepressure, after which the resin product is removed and separated fromthe water. Usually, the resin is then heated to a temperature of about-275 C. to expel dissolved gases, water and volatile organic materials.Other methods of preparing resinous substances by the digestion ofcellulosic materials in the presence of water may be employed ifdesired.

As will be apparent from the foregoing examples, the reaction by whichthe wood digestion resin is saponified to form the new emulsifying agenttakes place readily in the cold, although if desired it may be hastenedmaterially by mild heating. Ordinarily, it will be found preferablemerely to stir the finely divided resin into an aqueous solution of analkaline alkali-metal compound, such as sodium hydroxide, potassiumcarbonate, potassium hydroxide, ammonium hydroxide, etc., maintained atroom temperature or there-abouts. The proportion in which the alkalinesaponifying agent is employed depends somewhat upon the particular agentand the desired degree of saponification, but is usually between about 5and about 15 percent by weight of the wood digestion resin. Theproportion of water may be varied between wide limits whereby thesaponified product may range from a thin liquid containing 10 per centby weight or less of solids to a thick paste containing as high as 75per cent by weight of solids. If desired, it may be prepared in dry formby subjecting the aqueous product to drum or spray drying in the knownmanner.

Aqueous bituminous or asphaltic emulsions or dispersions areconveniently prepared with the aid of the new saponified wood digestionresin emulsifying agent by dispersing the latter in the aqueous phase,and thereafter adding the bituminous or asphaltic material in the moltenstate to the water in a fine stream and with rapid stirring. The mixtureis then passed through a suitable dispersing machine or colloid mill toform a stable emulsion. If desired, a small amount of a free alkali maybe added to th aqueous phase prior to emulsification for the purpose ofimproving the physical stability of the emulsion. Either naturalasphalts or bitumins, such as California, Texas, Venezuelan or Trinidadasphalts, or artificial bituminous materials, such as coal tar pitch,stearine pitch, petroleum pitches, etc., may be emulsified in thismanner. The emulsifying agent is usually employed in an amountrepresenting between 0.25 and about 10 per cent by weight, preferablybetween about about 0.75 and about 5 per cent by weight, of the aqueousphase, although the optimum proportion will depend upon the nature ofthe non-aqueous phase as well as the breaking characteristics desired inthe emulsion. In some instances it may be desirable to modify suchbreaking characteristics through the use of minor amounts ofotheremulsifying agents, such as fatty acid soaps, sulphonated oils, etc., orto include stabilizing agents, such as casein, glue, blood albumen,carbohydrates, etc,

The aqueous bituminous or asphaltic emulsions comprising the newsaponified wood digestion aa'zaeee resin emulsifying agent arecharacterized by excellent chemical stability, which, if desired,however, may be varied between wide limits to meet particular conditionsof application simply by varying the proportion of emulsifying agent.They also have good physical stability and do not separate or settleupon storage for long periods of time. The emulsifying agent itself ischaracterized by exceptionally low cost, being very readily manufacturedfrom materials heretofore largely considered as waste prodcts, and byexcellent emulsifying properties. For these reasons, it is particularlyadapted to use in preparing the herein described bituminous emulsions,which must of necessity be of low cost, although it maybe similarlyemployed with equal advantage in preparing aqueous emulsions ordispersions of a variety of other water-insoluble materials.

What I claim and desire to protect by Letters Patentis:

l. The saponification product of a water-soluble alkali and a wooddigestion resin, said wood digestion resin being the resin produced byheating a ligneous wood and a material selected from the groupconsisting of natural resin acids and materials containing natural resinacids, with water in amount sufficient to substantially completelysubmerge the wood under superatmospheric pressure at a temperaturewithin the range of about 240 C. to about 330 C. until the cellularstructure of the wood has disappeared and recovering said resin as theresidue remaining after removal of the water solution.

2. The sodium hydroxide saponiflcation product of a wood digestionresin, said wood digestion resin being the resin produced by heating aligneous wood and a material selected from the group consisting ofnatural resin acids and materials containing natural resin acids, withwater in amount sufficient to substantially completely submerge the woodunder superatmospheric pressure at a temperature within the range ofabout 240 C. to about 330 C. until the cellular structure of the woodhas disappeared and recovering said resin as the residue remaining afterremoval or the water solution.

within the range of about 240 C. to about 330 C. until the cellularstructure of the wood has disappeared and recovering said resin as theresidue remaining after removal of the water solution.

4. An aqueous bituminous emulsion comprising a bituminous material asthe dispersed phase, water as the contiuous phase, and an emulsifyingagent comprising the sodium hydroxide saponification product of a wooddigestion resin, said wood digestion resin being the resin produced byheating 'a llgneous wood and a material selected from the groupconsisting of natural resin acids and materials containing natural resinacids, with water in amount suflicient to substantially completelysubmerge the wood under superatmospheric pressure at a temperaturewithin the range of about 240 C. to about 330 C. until the cellularstructure of the wood has disappeared and recovering said resin as theresidue remaining after removal of the water solution.

5. An aqueous bituminous emulsion comprising a bituminous material asthe dispersed phase,

water as the continuous phase, and an emulsifythe wood undersuperatmospheric pressure at a temperature within the range of about240C. to about 330 C. until the cellular structure of the wood hasdisappeared and recovering said resin as the residu remaining afterremoval of the water solution.

substantially completelysubrnerge the wood under superatmosphericpressure at a temperature 6. An aqueous bituminous emulsion comprising abituminous material as the dispersed phase, water as the continuousphase, and an emulsirying agent comprising the saponifieation product ofa water soluble alkali and a wood digestionresin in an amountrepresenting between about 0.75 and about 5 per cent by weight of theaqueous phase, said wood digestion resin being the resin.

produced by heating a ligneous wood and a material selected from thegroup consisting oi natural resin acids and materials containing naturalresin acids, with water in amount sumcient to substantially completelysubmerge the wood un-' der superatmospheric pressure at a temperaturewithin th'e'range of about 240 C. to about 330 C.-

until the cellular structure or the wood has disppeared and recove 1said resin as the residue remg after removal. or the wate olon.

CERTIFICATE OF CORRECTION.

' e 576,1498. M y 2 9%.

ROBERT W. MARTIN.

It is hereby certified thet error appears in the printed specificationof the above numbered patent requiring correctiorl a follows: Page 5,second column, line 27, claim 5, strike out "0.75 and about 5 per centby weight of the aqueous" and insert 1nstead'--O.25 and about 10 per Icent by weight of theand that the said Letters Patent should be readwith this eorrection therein that the same may conform to' the record ofthe case in the Patent Office,

Signed and sealed this 18th day of September, A. D. 1914.5.

Leslie Frazer (Seal) Firet Assistant Commissioner of Patents.

